Theory:

Cube:
Cube is a special type of cuboid whose length, breadth and height are all equal.
cube.svg
Properties of cube:
1. Length, breadth and height all are equal.
 
2. Each edge of the cube is \(a\) units.
 
3. It has six square faces.
 
4. All the vertices are right angle.
 
5. Opposite sides of the cube are parallel and congruent to each other.
Lateral surface area:
\(L. S. A.\) \(=\) Area of front side \(+\) Area of back side \(+\) Area of left side \(+\) Area of right side
 
\(= (a \times a) + (a \times a) + (a \times a) + (a \times a)\)
 
\(= a^2 + a^2 + a^2 + a^2\)
 
\(= 4a^2\)
 
Lateral surface area of the cube \(= 4a^2\) sq. units.
Total surface area:
\(T. S. A.\) \(=\) Area of top side \(+\) Area of bottom side \(+\) Area of left side \(+\) Area of right side \(+\) Area of front side \(+\) Area of back side
 
\(= (a \times a) + (a \times a) + (a \times a) + (a \times a) + (a \times a) + (a \times a)\)
 
\(= a^2 + a^2 + a^2 + a^2 + a^2 + a^2\)
 
\(= 6a^2\)
 
Total surface area of the cube \(= 6a^2\) sq. units.
 
Important!
Total surface area is also called a surface area.